A lathe is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as zeroing, shaving, facing, cutting, tapping, drilling/boring, and turning down with tools that are applied to the workpiece to create an object with symmetry about that axis.

Stock Types

Reading a Part Drawing

This diagram shows each of the dimensions required to read and effectively use a part drawing. Important: The outer diameter (OD) will tell you what size shaft you need to use. The inner diameter (ID) will tell you the size of the hole of the shaft, make sure your part ID matches the drawing ID. The tolerance will tell you how much your part length can be off. If your part is not within the tolerance given by the part drawing, you will need to do one of the two things listed: If it's too short, you’ll need to redo your part. If it's too long, you can face/shave it down to length. **As you may realize, a part being too LONG is better than too short

Safety Precautions

1. Never use gloves while operating the lathe because it may get caught.
2. Hair tied back, safety glasses, make sure nothing loose is dangling over the lathe (e.g. hoodie strings, baggy clothes, jewelry).
3. Keep hands and body a safe distance from the cutting line and spinning parts on the lathe.
4. Be cautious of heat: The metal stock gets very hot quickly.
5. Always remove the tightening key from the chuck before starting the machine.
6. Ensure the lathe spins towards you when turned on.

Machine Setup and Operation

Turning on the Machine
Blue Lathe	Silver Lathe
Turn the knob down.	Turn the knob to 1.
Flip the switch to 1.	Flip the switch to 1.
Pull out the emergency-stop AKA the e-stop or red button (this goes for both lathes.) Push the green button and make sure it is lit up, and turn the black knob (right of the green button) to the LEFT.	Pull the red lever out and down and make sure the lathe is spinning towards you. NEVER let the lathe spin away from you.
The x axis corresponds to a forward and back movement, and the y axis corresponds to a side to side movement. This is consistent for both lathes, however keep in mind that the y axis on the blue lathe is referred to as the z axis on the silver lathe. Moving the x axis knob clockwise results in a forward movement, and moving the y/z axis clockwise results in a right movement.

Speed Settings

• Fastest speed: For cutting or shaving
• Slowest speed: For tapping

Basic Operations

Zeroing the Z/Y-Axis and X-Axis

Preparation

• Ensure the lathe is turned on and the workpiece is securely mounted in the chuck. The part should be more than 70% inside the machine clamps.
• Select the shaving bit and mount it in the tool post.

Reminders

• The Z-axis on the silver lathe corresponds with the Y axis on the blue lathe. 
• When zeroing, you don't want to remove too much material from your part. Even a thousandth of an inch can affect your measurements and potentially require remaking the part.
• Always approach the workpiece slowly and carefully to avoid damaging the tool or workpiece.
• Some machinists prefer to zero the Z-axis first, then the X-axis, but the order can be adjusted based on personal preference or specific job requirements.

X-Axis Zeroing

1. Slowly move the cutting tool towards the workpiece in the X-axis (radial direction).
2. Approach the surface of the workpiece very carefully.
3. Continue advancing the tool until you see very small chips forming.
4. This point of contact is your zero reference for the X-axis.
5. Set the X-axis digital readout (DRO) to zero at this point, if your lathe has one.

Z/Y-Axis Zeroing

1. Move the cutting tool to the end of the workpiece.
2. Slowly advance the tool in the Z-axis (along the length of the workpiece).
3. Approach the face of the workpiece very carefully.
4. Continue advancing until you see very small chips forming.
5. This point of contact is your zero reference for the Z-axis.
6. Set the Z-axis DRO to zero at this point, if available.

Shaving and Facing

Preparation

• Ensure the lathe is turned on and the workpiece is securely mounted in the chuck. The part should be more than 70% inside the machine clamps.
• Select the shaving bit and mount it in the tool post.

Shaving

1. Position the cutting tool approximately 0.01-.03 inches inward of the part.
2. Slowly rotate the x-axis handwheel clockwise to move the cutting tool towards the part. Maintain a consistent speed for the most accurate and clean results.
3. Cut in 0.01-.03 increments until you reach the middle of the part on the x-axis.
4. Once at the midpoint, stop the cutting process.
5. Rotate the Z-axis handwheel clockwise to move the cutting tool away from the part, ensuring clearance.

Facing

• The process for facing is the same as shaving, but the increments are much smaller: .005-.01”.
• Facing is used for the last few cuts of a part to achieve the smoothest edge. The smaller the increments, the better the cuts.

Tapping

Steps

1. Place your part at least 70% in the lathe.
2. Turn the speed setting to the lowest. This is essential, as going too fast will likely break or weaken the tap as they are very fragile.
3. Turn the black knob left and push the entire chuck mechanism gently towards your part until the tip of the tap is just against your part.
4. Slowly turn the wheel (pictured) clockwise until the chuck mechanism starts moving into the part on its own.
5. Once you’ve tapped halfway to the tap length, turn the black knob back to the center. 
6. Turn the black knob to the right to take the tap out of the part (this is the ONLY time the lathe should ever spin away from you).
7. Clean the tap and part with air.
8. Repeat this process, this time going all the way to your desired length.
9. Repeat this once again to ensure clear threads.

Tips and Best Practices

• "Measure twice, cut once" - Always double-check your measurements. You can’t make something longer but you can make it shorter.
• Face only .005-.01 of your part if the face is rough/jagged to ensure your part has a smooth face so that you can more accurately zero or set the part length in the machine
• Shave only 0.01-0.04 inches at a time for better control and finish.
• Use slow, consistent movements for optimal results.
• Use tapping fluid for tapping operations and cutting fluid for other cutting operations.
• When zeroing your part, approach slowly until you see very small chips to avoid removing too much material.